<p>The aim of cancer screening is to identify pre-malignant conditions, which can be removed or treated, or earlier-stage disease, for which treatment is more likely to be curative, in non-symptomatic individuals. Currently, screening programmes are being consolidated for five cancer types (breast, prostate, cervical, colorectal and lung) and several other cancer types are the focus of specific initiatives. Cancer screening is at a point of potential major transformation owing to technological advances in detection. In this Review, we first recapitulate the general principles of cancer screening. We then provide a timely overview of the current screening practices for breast, cervical, colorectal, prostate and lung cancer, addressing major challenges and potential future changes in practice. We also discuss other malignancies for which screening initiatives might be worth considering. Finally, we highlight technological developments in cancer detection that might hold promise for screening an increasing number of cancers in the future, notably some that reflect unmet needs.</p>